Technical field

The present invention relates to a sheet metal roofing element and a method and apparatus for manufacturing said sheet metal roofing element. Background art

A sheet metal roofing element is for example known from WO 9941471 A1 . This know sheet metal roofing element or tile has inter- engageable channels on its opposing longitudinal sides, one channel being on the underside and the channel on the upperside of the tile. A mounting tab extends from adjacent the upperside channel substantially co-planar to the body of the tile. The channels enable two tiles to be joined in an overlapping side by side relationship with their corresponding channel sections engaged. Each tile can be fixed to a supporting structure by their mounting tabs. A third tile can then be joined longitudinally of the first two tiles by engaging its underside channel over and about their joined upperside channel sections. It can also be fixed to the supporting structure and the steps repeated to sheath a desired area.

The manufacturing process of such roofing elements comprises steps of deforming a blank of sheet metal in a sheet metal pressing apparatus, to create strengthening grooves and decorative indentations, and subsequently further deforming the blank by means of a sheet metal folding apparatus to create the folded edges.

Disclosure of the invention

It is a first aim of this invention to provide a sheet metal roofing element with enhanced strength.

According to the present invention, the first aim is achieved with a sheet metal roofing element having the technical characteristics of the first independent claim. It is a second aim of this invention to provide a method and apparatus with which a wide variety of different sheet metal roofing elements having different decorative relief structures can be manufactured in an efficient way.

According to the present invention, the second aim is achieved with the method and apparatus according to the further independent claims.

In a first aspect, the present invention provides a sheet metal roofing element comprising a body, a first folded edge portion at a first longitudinal edge of the body forming a channel on what, in situ, will be an inner face of the roofing element, and a second folded edge portion at a second and opposite longitudinal edge of the body and forming a channel on what, in situ, will be an outer face of the roofing element, the folded edge portions being such that the first folded edge portion of a first such roofing element can be engaged with the second folded edge portion of a second such roofing element, the body being provided with strengthening indentations including a series of transverse strengthening grooves extending in transverse direction of the body and dividing the body up into a plurality of tile portions. The strengthening indentations further include longitudinal strengthening grooves extending in longitudinal direction of the body in between the transverse strengthening grooves without intersecting with the transverse strengthening grooves.

It has been found that, even though the longitudinal edges of the sheet metal roofing element are folded to form the first and second folded edge portions, the strength of the sheet metal roofing element can be highly enhanced by the provision of the longitudinal strengthening grooves while avoiding that they intersect with the transverse strengthening grooves.

In embodiments according to the present invention, the longitudinal strengthening grooves span at least 75% and preferably at least 80% of the length of the tile portion, and/or the longitudinal strengthening grooves span at most 95% and preferably at most 90% of the length of the tile portion. With said length of the tile portion being the distance between the transverse strengthening grooves adjacent to the tile portion. It has been found that such a span range is optimal for reinforcing the sheet metal roofing element.

In embodiments according to the present invention, the transverse strengthening grooves have a depth of at least 2,0 mm and preferably at least 2,5 mm, and/or the transverse strengthening grooves have a depth of at most 4,0 mm and preferably at most 3,5 mm.

In embodiments according to the present invention, the longitudinal strengthening grooves have a depth of at least 1 ,0 mm and preferably at least 1 ,5 mm, and/or the longitudinal strengthening grooves have a depth of at most 3,0 mm and preferably at most 2,5 mm.

In embodiments according to the present invention, the transverse strengthening grooves have a W-shaped profile.

In embodiments according to the present invention, the longitudinal strengthening grooves comprise, for each tile portion, a first longitudinal strengthening groove in the vicinity of the first folded edge portion and/or a second longitudinal strengthening groove in the vicinity of the second folded edge portion. The second longitudinal strengthening groove is preferably located underneath a back-folded part of the second folded edge portion, so that in use it is hidden from sight.

Arranging the longitudinal strengthening grooves in such a way, or more generally, in such a way that the transverse strengthening grooves and the longitudinal strengthening grooves together substantially surround each tile portion, offers the advantage that the periphery of the tile portions are strengthened in such a way that further indentations of the tile portions, such as for example the decorative relief structures described below, do not cause any deformations of the roofing element outside of each tile portion.

In embodiments according to the present invention, the tile portions are preferably of substantially the same size, although this is not essential. The transverse grooves are preferably continuous, i.e. extend throughout the entire width or transverse dimension of the roofing element, although this is not essential. The roofing element may be provided with a part at one transverse side which is intended for being overlapped by an adjacent roofing element and may be provided with a mounting tab extending from the second folded edge, by means of which the roofing element can be fixed to a roof structure.

In embodiments according to the present invention, the roofing element may comprise further indentations in the form of decorative relief structures on at least some of the tile portions in between the transverse strengthening grooves. The decorative relief structure may be the same for all the tile portions of the element, but may also differ. Some of the tile portions may also be left planar, without any relief structure.

In a second aspect, the present invention provides a method for manufacturing a sheet metal roofing element, comprising the steps of:

(a) providing a blank of sheet metal;

(b) deforming the blank by means of a sheet metal pressing apparatus, thereby forming indentations in the blank, the indentations including a series of transverse strengthening grooves extending in transverse direction of the blank and dividing the blank up into a plurality of tile portions; and

(c) further deforming the blank by means of a sheet metal folding apparatus to create a first folded edge portion at a first longitudinal edge of the blank, the first folded edge portion forming a channel on what, in situ, will be an inner face of the roofing element, and a second folded edge portion at a second and opposite longitudinal edge of the body, the second folded edge portion forming a channel on what, in situ, will be an outer face of the roofing element, the folded edge portions being made such that the first folded edge portion of a first such roofing element can be engaged with the second folded edge portion of a second such roofing element.

The second aspect of the invention is characterized in that the method further comprises the steps, before step (b) of deforming the blank by means of the sheet metal pressing apparatus, of (i) providing a plurality of sets of complementary tile portion deforming inserts with different relief structures, the tile portion deforming inserts being provided for being mounted on mould halves of the sheet metal pressing apparatus; and (ii) selecting, from said plurality of sets of complementary tile portion deforming inserts, those sets of complementary tile portion deforming inserts as needed for obtaining the desired relief structures upon deforming the blank in step (b) and placing these sets of complementary tile portion deforming inserts on the mould halves.

By providing the different relief structures by means of the plurality of sets of complementary inserts for the mould halves, the pressing apparatus can be quickly and efficiently converted from one configuration (in which the apparatus is provided for manufacturing a first type of roofing element) to another configuration (in which the apparatus is provided for manufacturing a second, different type of roofing element with different decorative relief structures). Furthermore, by providing separate, interchangeable inserts per tile portion, i.e. the decorative relief structure can be chosen per tile portion, it is clear that a wide variety of roofing elements can be manufactured using the same pressing apparatus by simply placing the appropriate inserts as desired.

In embodiments according to the present invention, for at least two of the tile portions sets of complementary tile portion deforming inserts with different relief structures are placed on the mould halves so as to obtain different decorative relief structures on at least two of the tile portions after step (b).

In embodiments according to the present invention, for at least one of the plurality of tile portions planar inserts are placed on the mould halves to maintain the respective tile portion planar, without any relief structure.

In embodiments according to the present invention, the indentations formed in the blank in step (b) further include longitudinal strengthening grooves extending in longitudinal direction of the body in between the transverse strengthening grooves without intersecting with the transverse strengthening grooves.

In embodiments according to the present invention, the longitudinal strengthening grooves that are created in step (b) comprise, for each tile portion, a first longitudinal strengthening groove in the vicinity of the first longitudinal edge of the manufactured roofing element and a second longitudinal strengthening groove in the vicinity of the second longitudinal edge of the manufactured roofing element.

In embodiments according to the present invention, the longitudinal strengthening grooves are dimensioned for taking up excess material in case little or no deformation occurs in the respective tile portion.

In the second aspect, the invention also provides a sheet metal pressing apparatus for use in a method for manufacturing a sheet metal roofing element. The sheet metal pressing apparatus comprises mould halves and means for pressing the mould halves onto each other and thereby deforming a blank of sheet metal to create indentations in the blank. The mould halves comprise complementary transverse parts for forming transverse strengthening grooves extending in transverse direction of the blank and dividing the blank up into a plurality of tile portions. The mould halves are provided for receiving a plurality of sets of complementary tile portion deforming inserts, provided for forming decorative relief structures on the tile portions of the blank in between the transverse strengthening grooves.

In embodiments according to the present invention, the mould halves comprise complementary longitudinal parts for forming longitudinal strengthening grooves extending in longitudinal direction of the blank in between the transverse strengthening grooves without intersecting with the transverse strengthening grooves.

In embodiments according to the present invention, the complementary longitudinal parts are positioned for forming the longitudinal strengthening grooves for each tile portion as a first longitudinal strengthening groove in the vicinity of a first longitudinal edge and a second longitudinal strengthening groove in the vicinity of a second longitudinal edge of the blank.

In embodiments according to the present invention, the complementary longitudinal parts are dimensioned for forming the longitudinal strengthening grooves such that they take up excess material in case little or no deformation occurs in the respective tile portion.

In the second aspect, the invention also provides a roofing element forming device comprising the sheet metal pressing apparatus according to an embodiment of the present invention.

Brief description of the drawings

The invention will be further elucidated by means of the following description and the appended drawings.

Figure 1 shows a perspective view on a sheet metal roofing element according to an embodiment of the present invention.

Figure 2 shows a top view on the roofing element of Figure 1 .

Figure 3 shows a side view on the roofing element of Figure 1 .

Figure 4 shows a detailed view on the first transverse edge of the roofing element of Figure 1 .

Figure 5 shows a detailed view on the second transverse edge of the roofing element of Figure 1 .

Figure 6 shows detailed view on a transverse strengthening groove of the roofing element of Figure 1 . Figure 7 shows a top view on a sheet metal roofing element according to an embodiment of the present invention.

Figure 8 shows a top view on a sheet metal roofing element according to an embodiment of the present invention.

Figure 9 shows a perspective view on a roofing element manufacturing device according to an embodiment of the present invention.

Figure 10 shows a perspective view on a mould halve of a sheet metal pressing apparatus according to an embodiment of the present invention.

Figure 1 1 shows a perspective view on tile portion deforming inserts for use in a sheet metal pressing apparatus according to an embodiment of the present invention.

Figure 12 shows the different steps of a method according to an embodiment of the present invention for manufacturing a sheet metal roofing element according to an embodiment of the present invention.

Modes for carrying out the invention

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein. The term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Figures 1 -6 show a sheet metal roofing element 10 according to an embodiment of the present invention from different views and with different detail, and Figures 7 and 8 show sheet metal roofing elements 10 according to alternative embodiments of the present invention.

The sheet metal roofing element 10 comprises a body having a substantially rectangular shape. A first and second longitudinal edge 101 , 102 of the body extend in a longitudinal direction on opposite sides of the body, and a first and second transverse edge 103, 104 of the body extend in a transverse direction on opposite sides of the body, with the transverse direction being substantially perpendicular to the longitudinal direction.

At the first longitudinal edge 101 of the body, the roofing element 10 comprises a first folded edge portion 1 1 1 folded downwards underneath the body. As such, the first folded edge portion 1 1 1 forms a channel 1 13 on what, when the roofing element 10 is used for covering a roof structure, will be an inner face 105 of the roofing element 10 facing towards the roof structure. At the second longitudinal edge 102 of the body, the roofing element 10 comprises a second folded edge portion 1 12 folded upwards over the body. As such, the second folded edge portion 1 12 forms a channel 1 14 on what, when the roofing element 10 is used for covering a roof structure, will be an outer face 106 of the roofing element 10, facing away from the roof structure. The folded edge portions 1 1 1 , 1 12 of the roofing element 10 have been folded in such a way that the first folded edge portion 1 1 1 of a roofing element 10 can be engaged with the second folded edge portion 1 12 of another roofing element 10 of the same type. At the second longitudinal edge 102 there extends a mounting tab 1 16 from the second folded edge portion 1 12, by means of which the roofing element 10 can be fixed to a roof structure. The mounting tab 1 16 extends substantially co-planar to the body of the tile.

The body is provided with strengthening indentations 12, 131 , 132 including a series of transverse strengthening grooves 12 and a series of longitudinal strengthening grooves 131 , 132, which provide additional strength to the roofing element 10.

The transverse strengthening grooves 12 extend in the transverse direction of the body and divide the body up into a plurality of tile portions 14, for example six tile portions 14 in this embodiment. The transverse strengthening grooves 12 have a W-shaped profile, such as for example can be seen in Figure 6.

The longitudinal strengthening grooves 131 , 132 extend in the longitudinal direction of the body in between the transverse strengthening grooves 12 without intersecting with the transverse strengthening grooves 12. Two longitudinal strengthening grooves 131 , 132 are provided in each tile portion 14, of which a first longitudinal strengthening groove 131 is arranged in the vicinity of the first folded edge portion 1 1 1 at the first longitudinal edge 101 of the body, and of which a second longitudinal strengthening groove 132 is arranged in the vicinity of the second folded edge portion 1 12 at the second longitudinal edge 102. Hereby, the second longitudinal strengthening groove 132 is located underneath a back-folded part 1 15 of the second folded edge portion 1 12, such that the second longitudinal strengthening groove 132 is hidden from sight in use.

In the embodiment of Figures 1 -6, the tile portions 14 are planar, but according to an embodiment of the present invention the tile portions 14 of the roofing element 10 may be provided with further indentations 15 in the form of decorative relief structures 15, such as shown in Figure 7. The decorative relief structures 15 are for example used to provide the sheet metal roofing element 10 with the look of a wooden or stone roofing element. Each tile portion 14 of the roofing element 10 may be provided with the same decorative relief structures 15, or a combination of different decorative relief structures 15 may be used, possibly in combination with planar tile portions 14.

At the first transverse edge 103 a part of the roofing element 10 is provided with further indentations 16 in the form of a series of parallel ribs 16 extending along the transverse direction of the body of the roofing element 10. This part of the roofing element 10 is provided for being overlapped by a part of an adjacent roofing element 10, which overlapping part is located at the second transverse edge 104 of said adjacent roofing element 10. The function of the ribs 16 is to prevent water, for example from rain, from flowing between the overlapping roofing elements 10 towards a roofing structure on which the roofing elements 10 are mounted.

At the corner between the second longitudinal edge 102 and the second transverse edge 104, at least the mounting tab 1 16 is omitted, such that when two adjacent roofing elements 10 are overlapping each other, as described above, the mounting tabs 1 16 of the overlapping roofing elements 10 do not obstruct each other. In the roofing element 10 of Figures 1 -6 only the mounting tab 16 is omitted in said corner of the roofing element 10, but according to alternative aspects of the present invention, shown in Figure 8, also the back-folded part 1 15 of the second folded edge portion 1 12 may be omitted completely or partially at said corner of the roofing element 10, such that no channel or only a partial channel 1 13 is formed by the second folded edge portion 1 12. In this way possible obstructions between adjacent overlapping roofing elements 10 are further reduced.

A roofing element manufacturing device 20, such as shown in Figure 9, may be used for manufacturing sheet metal roofing elements 10 according to an embodiment of the present invention. The roofing element manufacturing device 20 comprises a lift table 210 for storing blank sheets of metal 30 before being processed in the roofing element manufacturing device 20. The roofing element manufacturing device 20 may, however, also be provided in such a way that blank sheets of metal 30 are provided directly to the roofing element manufacturing device 20.

The roofing element manufacturing device 20 also comprises a sheet metal notching apparatus 220, which is provided for cutting out parts of the blank sheets of metal 30. Such a part being cut out from the blank sheets of metal 30, may for example be the corner part between the second longitudinal edge 102 and the second transverse edge 104, where in the final roofing element 10 the mounting tab 1 16 and optionally the back-folded part 1 15 of the second folded edge portion 1 12 are omitted. The roofing element manufacturing device 20 also comprises a sheet metal pressing apparatus 230 which is provided for deforming/indenting the blank sheets of metal 30 in order to form the strengthening indentations 12, 131 , 132, such as the transverse strengthening grooves 12 and the longitudinal strengthening grooves 131 , 132, and the further indentations 15, 16, such as the decorative relief structures 15 and the series of the parallel ribs 16. Furthermore, the sheet metal pressing apparatus 230 is also provided for pre-indenting the blank sheets of metal 30 in preparation of the folding of the blank sheets of metal 30 in the sheet metal folding apparatus 240 following the sheet metal pressing apparatus 230.

The sheet metal pressing apparatus 230 comprises opposing mould halves 231 of complementary shape, of which, for clarity reasons, only the bottom mould halve 231 is shown in Figure 9, and in more detail in Figure 10. The sheet metal pressing apparatus 230 also comprises means (not shown) for pressing the mould halves 231 onto each other with a blank sheet of metal 30 positioned in between them, thereby deforming/indenting the blank sheet of metal 30.

The mould halves 231 comprise complementary transverse parts 232 for forming the transverse strengthening grooves 12 of the roofing element 10. The mould halves 231 also comprise complementary longitudinal parts 233 for forming the longitudinal strengthening grooves 131 , 132 of the roofing element 10.

The mould halves 231 are provided for receiving a plurality of sets of complementary tile portion deforming inserts 234, of which some examples are shown in Figure 1 1 . The tile portion deforming inserts 234 are provided for forming the decorative relief structures 15 on the tile portions 14 of the roofing element 10. To form a planar tile portion 14, a planar surface tile portion deforming insert 234, such as shown in the bottom right corner of Figure 1 1 , may be used, or, alternatively, no tile portion deforming insert may be used.

The sheet metal folding apparatus 240 of the roofing element manufacturing device 20 is provided for folding the blank sheets of metal 30, thereby creating the first folded edge portion 1 1 1 and the second folded edge portion 1 12 of the roofing element 10 according to an embodiment of the present invention. The sheet metal folding apparatus 240 comprises opposing mould halves 241 between which the pre-indented blank sheets of metal 30 are pressed before being folded. The sheet metal folding apparatus 240 also comprises means (not shown) for moving said mould halves 241 relative to each other in the transverse direction when a blank sheet of metal 30 is positioned in between them, thereby folding the blank sheet of metal 30.

The method for manufacturing the sheet metal roofing element 10 according to an embodiment of the present invention by means of a roofing element manufacturing device 20 according to an embodiment of the present invention is illustrated in Figure 12, which shows the shape of a blank sheet of metal 30 in the different steps of method. The top row of Figure 12 shows the top view of the blank sheet of metal 30, the bottom row shows a side view of the blank sheet of metal 30.

In a first step A, a substantially rectangular blank sheet of metal 30, showing no deformations, is provided to the roofing element forming device 20, either directly or from the lift table 210, or by any other suitable means known by the skilled person.

In a second step B, the blank sheet of metal 30 is transported to the sheet metal notching apparatus 220 by suitable transportation means. At the sheet metal notching apparatus 220 predetermined parts of the blank sheet of metal 30 are cut out of the blank sheet of metal 30.

In a third step C, the blank sheet of metal 30 is transported from the sheet metal notching apparatus 220 to the sheet metal pressing apparatus 230 by suitable transportation means. In the sheet metal pressing apparatus 230 the blank sheet of metal 30 is deformed between the two mould halves 231 of the sheet metal pressing apparatus 230 for forming the transverse strengthening grooves 12, the longitudinal strengthening grooves 131 , 132, the decorative relief structures 15 and the series of the parallel ribs 16. Additionally, the blank sheet of metal 30 is also pre-indented for later folding in a following step D.

Step C is divided in different sub-steps C1 , C2, C3 which are applied progressively. This offers the advantage of preventing cracks in the blank sheet of metal 30, which cracks are more likely to occur when the entire blank sheet of metal 30 is deformed at once. In a first sub-step C1 a middle section of the blank sheet of metal 30 is deformed, after which the adjacent side sections of the blank sheet of metal 30 are deformed in a second sub-step C2. In a third sub-step C3, the blank sheet of metal 30 is then pre-indented in preparation for later folding. It should be clear to the skilled person that sub- steps C1 and C2 may be divided in further sub-steps. It should also be clear to the skilled person that sub-step C3 may also be part of the following step D of folding the blank sheet of metal 30 in the sheet metal folding apparatus 240.

In a fourth step D, the blank sheet of metal 30 is transported from the sheet metal pressing apparatus 230 to the sheet metal folding apparatus 240 by suitable transportation means. In the sheet metal folding apparatus 240 the blank sheet of metal 30 is folded by means of the two mould halves 241 of the sheet metal folding apparatus 240 for the first folded edge portion 1 1 1 and the second folded edge portion 1 12 of the roofing element 10.

References

10 roofing element

101 , 102 first and second longitudinal edge

103, 104 first and second transverse edge

105, 106 inner and outer face

1 1 1 , 1 12 first and second folded edge portion

1 13, 1 14 channel

1 15 back-folded part

1 16 mounting tab

12 transverse strengthening groove

131 , 132 first and second longitudinal strengthen!

14 tile portion

15 decorative relief structures

16 rib

20 roofing element manufacturing device

210 lift table

220 sheet metal notching apparatus

230 sheet metal pressing apparatus

231 mould halves

232 complementary transverse parts 233 complementary longitudinal parts

234 complementary tile portion deforming inserts

240 sheet metal folding apparatus

241 mould halves

30 blank sheet of metal